Packing gland for centrifugal pumps



16 1943. J. G. DoRwRD, .1R 2,334,396

YACK'ING GLAND FOR CENTRIFUGAL PUMPS INVENTOR.

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Filed Dec. 16, 1940 ATTORNEY,

support and drive Patented Nov. 16, 1943 2,334,396 PACKING GLAND FoRCENTRIFUGAL PUMPS John G. Dorward, Jr., Alameda, Calif.

Application December 16, 1940, Serial N0. 370,308

' (ci. 28s-7) 8 Claims.

.This invention relates to centrifugal pumps,

and especially to the stumng box or gland which surrounds the impellershaft of the pump.

In many instances the impeller of a eentrifugal pump is secured to anddirectly driven by the shaft of an electric motor. In such structures nobearings are formed in the pump housing which encloses the impeller, asthe bearings in the motor itself are designed to take care of both therotating element of the motor and the impeller. A stuiing box or glandis, however, required where the shaft enters the pump housing,

and as the shaft, or in other words the portion thereof which enters thehousing, in order to the impeller, is made as short as possible, thecouple between the motor and pump obviously reaches a minimum. Clearancespace and accessibility to insert and replace packingy is similarlyreduced, and if the gland is not given proper care, excess wear andleakagewill soon develop.

The object of the present invention is generally to improve and simplifythe constructionand operation of packing' glands of the characterdescribed; to provide a packing gland which is accessible regardless ofthe close spacing between the motor and pump; to provide a packing glandwhich is cartridge-like in construction and removable as a unit from theinner side of the pump cover; and further, to provide a cartridgelikepacking gland from which the packing itself may be readily removed andnew packing replaced whenever required. v

The packing gland is shown by way of illustration in the accompanyingdrawing, in which Fig. 1 is a side elevation, partially in section,showing one type of motor-driven pump, to which the packing gland may beapplied; and

Fig. 2 is an enlarged central vertical section of the. packing gland,said ew alsoshowing a portion of the motor shaft, and the pump cover andthe impeller. f

Referring to the drawing in detail, and especially to Fig. 1, anelectric motor driven centrifugal pump of the ejector type is shown inwhich A indicates the electric motor, B the volute or pump housinghaving a suction intake 2 and a discharge connection 3, and an auxiliarydischarge or by-pass 4 through which a portion of the water dischargedby the impeller C is bypassed and directed downwardly through a pipe 5to operate an injector 6 mounted in the suction or inlet pipe 1 of thepump. Pumps of .this character are well known and are extensively usedwhere the pump is mounted above a well or similar source of -watersupply.

In pumps of this kind, speed is most essential in maintaining eillciencyand low cost of production; hence motors of 3600 R. P. M. are mostsuitable. However, due to the high speed and the fact that thepumpimpeller is secured directly to the motor shaft, a close couplingmust be maintained between the motor and pump to avoid eccentricity ofthe motor shaft, which mightycreate an unbalanced and unsatisfactoryoperating condition. To permit the close coupling required, thelowerbell 8, and particularly the base 9 of the motor, is in thisinstance employed to function as the pump cover. The motor shaft I0 mustaccordingly extendtherethrough, and as this is the case, a stuffinggland,

generally indicated at Dwill also be required to prevent water and gritfrom entering the motor. The low stature of the pump and the short motorshaft would ordinarilypresent problems in packing the shaft, as it canreadily be seen that the low structure prohibits the use of any.conventional type of packing gland on the top side of the cover 9encasing the impeller o f the pump.

Furthermore, it would be impossible to get-at the packing for adjustmentand renewal, as the packing is inacessible through the small windows IIleading into the limited space between the lower end of the motorand'the cover encasing the impeller. I therefore have provided anabbreviated cone I2 on the cover encasing the impeller, and on theunderside of the cone a recess is formed in which is inserted acartridge 4packing gland D, detachably secured to the cone of the coverencasing the impeller by means of a screw thread.

The cartridge packing gland D is fully illustrated in Fig. 2; andbesides functioning efilclently as a packing for the shaft, it must alsoovercome and eliminate obstacles detrimental to the successful operationof the pump, namely:

Accessibility for renewal or replacement is provided for by aself-contained cartridge encasing the packing assembly, which is screwedinto or easily removed from the cone I2 of the pump cover. It is readilyaccessible by removing the impeller C by putting asocket wrench on ahexagonal hub/ I4 of the impeller and another wrench on a fiat I5 of themotor shaft, and unscrewing the impeller from the motor shaft. Then b-y'applying a wrench on a hexagonal exterior surface of the body of thecartridge packing gland, the whole packing assembly can be repacked inplace or the entire packing box can" be quickly 'replaced with a newunit, and the old cartridge can be reloaded for future use. This featuresaves much time and cost, as compared to the conventional type ofpacking gland that has to be repacked from the top side; and inconnection with pumps described above, Where the space is so limited, itrequires much more time and expense to replace the 'conventional type ofpacking while in place.

- -'Another feature in favor of putting the packbe as free from frictionlosses as possible. is provided for by the use of a series of especiallying in from the bottom is that there is no danger of injuring the sharpfin edges of the V rings I8, as the V packing rings slide over the motorshaft back side first and this prohibits any possible v'injury totheessential sharp and delicate edges of the V rings.

lAnti-friction packing is another advantage derived, because any packingused on ejector pumps and especially those of small horse power mustThis ltreated leather V rings I8 and a lubricated felt V ring I9. TheseVv rings are held in place at the top with a special form fitting brassretainer ring- 20 and a brass expander ring 2| on .the

K bottom. l

spring 22 is provided for holding the pack- `ing7rings in their workableposition, but this spring, unlike most spring loaded packing glands,Ahas no other function than to keepythe pack- "ing in its position andto allow for freedom ofY "the packing, due to expansion from theswelling of the packing rings. Spring tension is most essential on othertypes of spring loaded packing, buton the packing illustrated above thespring is not depended on as the water pressure-does the sealing of thepacking automatically by pressure on the expander ring 2I, the

, \V felt ring I9, and the leather V rings I8.

A renewable shaft sleeve is provided in the form of a specialnon-corrosive high nickel bronze sleeve 23 slipped over the shaft andclamped in place between the impeller and the spacer collar 24, and notonly protects the motor shaft from wear and corrosion, but reducesfriction against the packing to a minimum. A special feature of thissleeve is that the design of the packing gland permits the sleeve to beturned end forend when the sleeve becomes worn, while in contact withthe V ring packing and by reversing the sleeve, the other end engagingthe new packing rings and thereby giving the sleeve double life.

l A high grade felt ring 25 is clamped between two brass washers 26 bythe spring 22 on the top and the snap ring I E on the bottom, and

thus serves as a `felt filter ring. The felt ring allows only filteredwater to seep through and iills the chamber or reservoir 21 full ofclean and grit-,free water. As there is no flow of water at any timethrough the V packing rings, the reservoir 21 remains full of filteredwater, and as the felt lter ring 26 also is not subjected to a flow ofwater, there is no circulation, thus eliminating any chance of grit ordirt working through. Therefore, it will be noted that any slight amountof water consumed in lubricating the V rings -I8 of packing comes fromthe reservoir 21 of clean filtered water.` and protects the V packingfrom wear and tear, which would occur if dirty wate'r was allowed tocontact the V packing rings.

Exhaustive tests have proven that the reservoir of ltered water is animportant element in assuring exceedingly long life to the whole packingassembly.

The operation is as follows: when the pump is primed and the airexhausted through the vent cock 28 (see Fig. 1) vthe water seeps throughthe filter felt 25 (see Fig. 2) and fills the reservoir 21 full of cleanfiltered water. Then when the pump is started, the pressure generatedtransmits pressure through the filter felt ring 25 and onto the water inthe reservoir v21 which in turn automatically exerts pressure on theexpander ring 2I which transfers pressure to the V rings I8 and I9 ofthe packing which seal the puter surface of the shaft sleeve 23 and theinner wall 29 .of the cartridge packing body or shell.

While these and other features of my invention have been more or lessspecifically describedI for purposes of illustration, I Wish itunderstood that various changes may be resorted to in construction andoperation, all within the scope of the appended claims.

`Having thus described my invention, what I claim and desire to secureby Letters Patent is:

1. A packing gland comprising a cylindrical shell having an annularinturned shoulder at one end, a returning ring engaging said shoulder,an expander ring spaced therefrom, a plurality of packing ringsinterposed between the retainer and the expander ring, said packingrings being V-shaped in cross section, a semi-porous packing and waterfilter gasket spaced from the expander ring to form a chamber for wateritered through the semi-porous gasket, and detachable means securingthelast named gasket within the shell.

2. A packing gland comprising a cylindrical shell having an annularinturned shoulder at one end, a retaining ring engaging said shoulder,an expander ring spaced therefrom, a plurality of packing ringsinterposed between the retainer and the expander ring, saidv packingrings being V-shaped in cross section, a semi-porous packing and waterfilter gasket spaced from the expander ring to form a chamber for waterfiltered through the semi-porous gasket, detachable means securing thelast named gasket Within the shell, and means maintaining a spacingbetween the semi-porous gasket and'the expander ring.

3. A packing gland comprising a. housing member, a retaining ringsecured in said housing, an expander ring spaced therefrom, a pluralityof packing rings and a lubricating ring interposed between said retainerand expander rings, a, semi-porous packing and water lter gasket spacedfrom the expander ring to form a chamber for water therebetween, anddetachable means for securing said last named gasket within saidhousing.

4. A packing gland comprising a housing member, a retaining ring securedin said housing, an expander ring spaced therefrom, a plurality ofpacking rings and a lubricating ring interposed between said retainerand expander rings, said packing rings and said lubricating rings beingV-shaped in cross section, a semi-porous packing and water iilter gasketspaced from said expander ring to form a chamber for water filteredthrough said semi-porous gasket for lubrication of said packingrings,and detachable f means securing the last named gasket within thehousing.

5. A packing gland comprising a cylindrical shell having an annularinturned shoulder at one end, a retaining ring engaging said shoulder,an expander ring spaced therefrom, a plurality of packing ringsinterposed between the retainer and the expander ring, said packingrings being V-shaped in cross section, a semi-porous packing and Waterfilter gasket spaced from the expander ring to form a chamber for waterltered through the semi-porous gasket, detachable.y means securing thelast named gasketl within the shell, and a compressing spring in thewater-receiving chamber to maintain the packing rings under slightcompression and the semi-porous gasket against the detachable securingmeans.

6. In combination with a pump cover of the character described and adriving shaft extending therethrough, a recess formed in the inner faceof the cover concentric to the shaft, a cythe driving shaft to extendcentrally and longitudinally therethrough, a retainer and an exlindricalshell, detachable means for securing the shell in the recess in aposition to permit the driving shaft to extend centrally andlongitudinally therethrough, a retainer and an expander ring within theshell, a plurality of packing rings Aing therethrough, a recess formedin the inner face of the cover concentric to the shaft, a cylindricalshell, detachable means for securing the shell in the recess in aposition to permit the driving shaft to extend centrally and longitudi-`nally therethrough, a retainer and an expanderi ring within the shell, aplurality of packing rings interposed between the retainer and theexpander rings to prevent water leakage through the shell, a semi-porouspacking and water iilter gas-l ket spaced from the expander ring to forma chamber Within the shell for water filtered` through the semi-porousgasket, a spring in the chamber maintaining the space between saidgasket and the expander ring, detachable means Vsecuring the semi-porousgasket, the spring, the

expander ring, andlthe'packing rings within the` shell, and a wearingsleeve cn that portion of the driving shaft which extends through theshell, said sleeve beinglend-to-end reversible.

8. In combination with a pump cover of the character described and adriving shaft extending therethrough, a recess formed in the inner faceof the cover concentric to the shaft, a cylindrical shell, detachablemeans for securing the shell in the recess in a position to permitpander ring within the shell, a plurality of packing rings and alubricating ring V-shaped in cross section interposed between theretainer and the expander rings to prevent water leakage through t e,shell, a semi-porous packing and water filter g sket spaced from theexpander ring to form a chamber within lthe shell for' water filteredthrough the semi-porous gasket. a @ring in the chamber maintaining ,thespace 1 between said gasket and, the expander ring, de-

tachable means securing the semi-porous gasket, the spring, theexpander-ring, and the packing rings within the shell, and a wearingsleeve on that portion of the driving shaft which extends through theshell, said sleeve being endto-end reversible.

JOHN G. DORWARD, Ja.

